This course is to introduce additive combinatorics. It basically follows the lecture note by Terence Tao [01], with necessary modification at need. It will start at the combinatorial estimates relating to the sums, differences, and products of finite sets. We will also cover related objects such as arithmetic progressions, from the classical theorem by van der Waerden to the Szemeredi’s theorem for the case of k = 3. Various tools as well as related topics will also be touched.